Non-bridging contact via structures in proximity
A first photoresist layer is patterned with a first pattern that includes an opening in a region between areas of two adjacent via holes to be formed. The opening in the first photoresist is transferred into a template layer to form a line trench therein. The lateral dimension of the trench is reduced by depositing a contiguous spacer layer that does not fill the trench completely. An etch-resistant material layer is conformally deposited and fills the trench, and is subsequently recessed to form an etch-resistant material portion filling the trench. A second photoresist layer is applied and patterned with a second pattern, which includes an opening that includes areas of two via holes and an area therebetween. A composite pattern of an intersection of the second pattern and the complement of the pattern of the etch-resistant material portion is transferred through the template layer.
1. A structure comprising:
a stack of a template layer and a contiguous spacer layer overlying said template layer, wherein said template layer is composed of a first dielectric material and said contiguous spacer layer is composed of a second dielectric material;
an etch-resistant material portion overlying a recessed portion of said stack, wherein said etch-resistant material portion is composed of a third dielectric material having an etch resistance greater than an etch resistance of each of said first dielectric material and said second dielectric material; and
a pair of via structures embedded within said stack and laterally spaced and directly contacted by said etch-resistant material portion and said recessed portion of said stack, wherein each of said pair of via structures comprises a conductive material,
wherein a first portion of said template layer located between said pair of via structures and underlying said etch-resistant material portion has a lesser thickness than a second portion of said template layer contacting a sidewall of one of said pair of via structures, and
wherein a first portion of said contiguous spacer layer contacts a top surface of said first portion of said template layer, and a second portion of said contiguous spacer layer contacts a top surface of said second portion of said template layer.
2. The structure of claim 1 , wherein an entirety of said contiguous spacer layer is contiguous, and said contiguous spacer layer has a same thickness in said recessed portion of said template layer as in a non-recessed portion of said template layer.
3. The structure of claim 1 , wherein said etch-resistant material portion has a rectangular portion that laterally contacts said pair of via structures.
4. The structure of claim 1 , wherein said etch-resistant material portion comprises a dielectric metal oxide.
5. The structure of claim 1 , wherein a top surface of said contiguous spacer layer, a top surface of said etch-resistant material portion, and top surfaces of said pair of via structures are substantially coplanar among one another.
6. The structure of claim 1 , wherein said etch-resistant material portion has an H-shaped pattern, and a lateral extent of said pair of via structures is bounded by a pair of parallel line portions within said H-shaped pattern.
7. The structure of claim 1 , wherein said etch-resistant material portion has a rectangular shape, and said pair of via structures is separated along a widthwise direction of said rectangular shape.
8. The structure of claim 1 , wherein etch-resistant material portion has a sub-lithographic lateral dimension for deep ultraviolet lithography.
9. The structure of claim 1 , wherein said first portion of said contiguous spacer and said second portion of said contiguous spacer have a same thickness.
10. The structure of claim 1 , wherein said first portion of said contiguous spacer contacts a bottom surface of said etch-resistant material portion.
11. The structure of claim 1 , wherein each of said pair of via structures has three sidewalls in physical contact with sidewalls of said etch-resistant material portion and one sidewall that is not in physical contact with said etch-resistant material portion.
12. The structure of claim 11 , wherein each of said three sidewalls is in physical contact with a sidewall of said contiguous spacer layer.
13. The structure of claim 12 , wherein each of said three sidewalls is in physical contact with a sidewall of said template layer.
14. The structure of claim 1 , wherein said etch-resistant material portion has an overall shape of an “H”.
15. The structure of claim 1 , wherein a top surface of said etch-resistant material portion is coplanar with a top surface of said contiguous spacer layer.
16. The structure of claim 1 , wherein a sidewall of one of said pair of via structures and two sidewall surfaces of said etch-resistant material portion are within a same vertical plane.
17. The structure of claim 1 , wherein top surfaces of said pair of via structures is coplanar with a top surface of said etch-resistant material portion.
18. The structure of claim 17 , wherein said top surfaces of said pair of via structures is coplanar with a top surface of said contiguous spacer layer.